9-cis retinoic acid, which is an endogenous retinoic acid isomer, is capable of binding to both RARs and retinoid X receptors (RXRs). In order to study the ligand binding and other properties of this retinoic acid, we needed to synthesize [3H1]9-cis retinoic acid. Initially, we planned to develope a synthetic strategy for making cold 9-cis retinoic acid and then extend this strategy to the synthesis of "hot" 9-cis retinoic acid. We have completed the synthesis of the cold 9-cis retinoic acid and are currently working on the synthesis of radioactive 9-cis retinoic acid.